The present invention relates generally to turbocharger systems used with internal combustion engines in vehicles, and more particularly to intercooler assemblies used with turbocharger systems in vehicles.
Many high output turbocharged engines used in vehicles employ a base boost at relatively low engine speeds, such as during steady state highway driving. This base boost is essentially an always-on turbo boost and helps reduce turbo lag, which is a common complaint for older turbocharged engines on vehicles. A high level of base boost, together with a high thermal efficiency charge-air-cooler (CAC) heat exchanger (i.e., an intercooler), can cause condensation to form inside the CAC. This condensation typically occurs during steady state driving when ambient conditions are warm with humidity levels near one hundred percent. Such a condition may occur for an automotive vehicle during steady state highway driving in the rain.
The concern with forming this condensation occurs when a significant amount of condensate has been generated during steady state driving, and the vehicle operator subsequently performs a hard acceleration of the vehicle. The collected condensate can be ingested into the engine at too high of a rate, causing engine misfire. If the misfire is severe enough, the vehicle's engine control module may light the “service engine soon” light, which is undesirable. Moreover, the driver may also notice poor vehicle performance or rough acceleration, which are also undesirable.
One way to minimize the condensate collection is by employing a turbocharger system that provides a very low base boost. However, this increases the undesirable turbo-lag that base boost is meant to minimize in the first place. Another possibility to deal with the condensate is to use engine vacuum to extract condensate, but this may create powertrain integration concerns. Also, another way is to allow the condensate to leak to atmosphere; however, this may be undesirable when attempting to meet certain vehicle emissions requirements.
Another possible solution is to create an integrated condensate trap, as is shown in FIG. 1. In this turbocharger system 10, a pair of integrated condensate trap tubes 12 are built into the bottom of an intercooler heat exchanger 14. As air passes from an inlet tube 16 at a first end of the heat exchanger 14 to an outlet tube 18 at a second end of the heat exchanger, excess condensate that is formed in the heat exchanger 14 is stored in the integral trap tubes 12. For example, for a vehicle traveling at steady state highway speeds during a rain storm, the condensate may be produced in the intercooler heat exchanger 14 at a rate of about two hundred milliliters of water per hour, but the engine may only be able to handle ingesting water at a rate of about sixty milliliters of water per hour from the intercooler heat exchanger before engine misfire is detected. Thus, with the condensate trap tubes 12, the vehicle may only be able to travel for a relatively limited time before the ingestion rate of the condensate is high enough to cause a misfire.